Optimal Scheduling of FTPSS With PV and HESS Considering the Online Degradation of Battery Capacity

Abstract

To improve the power quality (PQ) and eliminate the neutral zone (NZ), a flexible traction power supply system (FTPSS) was proposed to provide flexible interfaces for hybrid energy storage system (HESS) and photovoltaic (PV). However, in order to realize the optimal scheduling of FTPSS, it is necessary to further study the high cost of HESS and battery available capacity. In this study, a two-layer model with the lowest comprehensive cost as the goal is proposed, which includes the cost of investment, replacement, operation and maintenance (O&M), and electricity. In the upper layer, the HESS sizing and replacement strategy are performed to achieve the lowest daily comprehensive cost within the project period. In the lower layer, based on the piecewise linear method, the battery capacity degradation is formulated as a linear mathematical model concerning the depth of discharge (DOD). Then, with the aim to achieve the lowest electricity charge, a mixed-integer linear programming (MILP) model is formulated by associating PV, regenerative braking energy (RBE), and HESS. Sparrow search algorithm (SSA) with CPLEX solver embedded is utilized to solve this two-layer nonlinear model. Finally, the simulation results show that the proposed model can achieve a 13.55% cost reduction.